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Audio interference with wired mic

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Brent Lane
Audio interference with wired mic
on Jul 6, 2011 at 4:59:05 am

Greetings. Glad to have found this community. I've read some old posts (~2007) but wanted to get a couple current opinions.

I've been getting audio interference/static on my Sony consumer HDR-HC1 HDV video camera when using a battery-powered, wired mono microphone. It was notable with a cheap Radio Shack mic (tiny battery), and worse with a much nicer Sony mic (larger AA battery). The Sony is XLR and connects to a XLR to 1/8" stereo converter I bought. The Radio Shack mic was 1/8" but I had a stereo converter on it.

From reading other posts (from Ty) that the interference/static may be related to a voltage problem relating to the mic power and that this may be a solution: http://www.trewaudio.com/store/product.php?productid=146&cat=21&page=1

Am I understanding this correctly? Is this what I need to buy? I'm assuming my camera jack is stereo and that the mic is mono.

Thanks for any help. I've been able to largely isolate the noise in the recording I have, but really want to fix this before I record anything else.


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Richard Crowley
Re: Audio interference with wired mic
on Jul 6, 2011 at 7:09:54 am

There could be several problems. But sorting them out would require more information. It would be helpful to know:
1) the exact model numbers of the microphones.
2) how the adapters are wired.
3) listening to a sample of the noise

You may not know #2, but you may need to get out a meter and measure it if you can't open the connectors and trace the wires.

If you can post an UNcompressed 10-20 second sample online somewhere, it would make it easier to diagnose. Not everyone uses the same terminology when describing audio artifacts.


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André Engelhardt
Re: Audio interference with wired mic
on Jul 6, 2011 at 10:03:34 am

Hi Brent,

in addition to Richard's suggestions, am I right in assuming that this only happens when using battery powered mics? Otherwise the sound is fine with other mic's?

Usually the first thing that comes to mind would be a bad connection / dirt / oxidized connectors when you get static with wired mics, then comes interference and then technical design issues (such as voltage mismatch etc,).

Before buying any converters/adpaters etc. I'd try to isolate the problem and see if it isn't something simple first. And yes, a short audio sample of the noise would be great.

--
Audio Engineer, Sound Designer
Video- and Photographer
http://www.andreengelhardt.net


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Ty Ford
Re: Audio interference with wired mic
on Jul 6, 2011 at 12:54:15 pm

Hello Brent and welcome tho the Cow Audio Forum.

"The Sony is XLR and connects to a XLR to 1/8" stereo converter I bought."
Which converter?

Is the noise generated by your moving the gear? You could have a worn input jack on the camera or bad connectors in your adapters or just the wrong plumbing of the plugs and/or jacks.

Yes, do post some samples if you wish, but the cable you posted enables you to plug a mono XLR mic into a stereo 1/8" camera input. And it blocks the DC bias voltage that can be a problem for some mics. If your mic requires external phantom power, you will still need something to provide that.

Regards,

Ty Ford

Cow Audio Forum Leader
Want better production audio?: Ty Ford's Audio Bootcamp Field Guide


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Brent Lane
Re: Audio interference with wired mic
on Jul 7, 2011 at 2:09:41 am

Thank you all so much for looking into this with me. I really appreciate it.

The mics are:

AudioTechnica A TR-3350 Omnidirectional Lavalier Microphone First one

(http://www.amazon.com/Audio-Technica-ATR-3350-Omnidirectional-Condenser-Mic...)

Sony ECM-44B Recent one

(http://www.amazon.com/Sony-ECM-44B-Microphone-black/dp/B0002M1VBI/ref=sr_1_...)


The XLR to 1/8" converter is:

Hosa XVS101F Right Angle 3.5 mm M to XLR F 1 foot

(http://www.amazon.com/gp/product/B000068NZG/ref=ox_sc_act_title_2?ie=UTF8&m...)


The noise is not associated with moving the equipment, although I can generate unwanted noise by jiggling the plug in the input jack. The noise is present with the mic power is turned on, and is slightly better if I hold the above converter while recording. The below sample is a WAV clip of it.

http://www.filexoom.com/showfile-28383/brent_lane_sample_buzz.wav


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Eric Toline
Re: Audio interference with wired mic
on Jul 7, 2011 at 6:38:07 am

The link for the sound sample doesn't work. On screen message says it's a 404, link not found.


Eric


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Ty Ford
Re: Audio interference with wired mic
on Jul 7, 2011 at 10:59:21 am

Brent,

Look at the description of the cable by the seller.

"A Hosa Cable which was designed for certain Stereo Microphones that use a single XLR as output for both Left and Right signals."

What led you to buy this cable?

Regards,

Ty Ford

Cow Audio Forum Leader
Want better production audio?: Ty Ford's Audio Bootcamp Field Guide


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Brent Lane
Re: Audio interference with wired mic
on Jul 7, 2011 at 12:50:51 pm

Sorry for the broken link. This one should work:

http://www.imagecabin.com/index.php?view=3100427511ad671a63f090d84&html=1


Ty: I bought this one because I was trying to go from XLR to 1/8 and thought this was what would do it. Is the stereo aspect the problem?

Big thanks to you all!


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Ty Ford
Re: Audio interference with wired mic
on Jul 7, 2011 at 1:59:09 pm

very much so!

Ty

Cow Audio Forum Leader
Want better production audio?: Ty Ford's Audio Bootcamp Field Guide


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